Firing units employed in weapon systems, aerospace systems, and other systems often include an electronics assembly and an initiation device. A firing unit containing an electronics assembly and an initiator/detonator may be utilized to initiate downstream energetic materials. Energetic materials, such as explosive materials, pyrotechnic materials, propellants and fuels, may be initiated with a variety of different types of energy including heat, chemical, mechanical, electrical, or optical. For example, energetic materials may be ignited by flame ignition (e.g., fuzes or ignition of a priming explosive), impact (which often ignites a priming explosive), chemical interaction (e.g., contact with a reactive or activating fluid), or electrical ignition. Electrical ignition may occur in one of at least two ways. For example, a bridge element may be heated until auto ignition of the adjacent energetic material occurs, or the bridge element may be exploded by directly detonating the adjacent energetic material. Providing a proper signal structure may cause a firing unit to initiate a pyrotechnic or explosive charge, which may then activate an ordnance device for a specific motor event. These motor events may include motor initiation, stage separation, thrust vector control activation, payload faring ejection and separation, etc.
A firing unit may include an energetic material secured within a housing, an initiation device configured to ignite the energetic material, and an electronics assembly electrically connected to the initiation device. Conventional firing units generally consume large amounts of energy and therefore require large batteries to operate. Furthermore, conventional firing units may be susceptible to inadvertent activation due to stray energy in the surrounding environment. Special precaution must be taken in the implementation of the firing unit and integrated initiator or detonator to control the affects of the environment in order to minimize the probability of an inadvertent initiation. The electronics assembly may prevent firing of the initiator/detonator until armed, communicates with the upstream electrical system, and upon receipt of a proper firing signal delivers the correct current pulse to the initiator bridge element. An electrical initiator/detonator may incorporate, in a sealed housing, an electrical connection to the electronics assembly, the bridge element, and the energetic material. The firing unit may be used to initiate rocket motor igniters, pressure cartridges, detonating cords, destruct charges, separation charges, payload release mechanisms, power system, warheads, gas generators, etc. These firing units may be employed in weapon systems (tactical and strategic for both ground and flight operations), aerospace systems (e.g., space launch vehicles, aircraft emergency egress), automotive airbag deployment systems, airdrop systems (e.g., parachute deployment, severance), mining and demolition systems, etc.